Equatorial countries have a maximum summer temp of maybe 32c and minimum winter temp of maybe 26c two seasons, a bit hot and a bit chilly. Which zone do these countries get placed. Example Sri Lanka aka Ceylon but Southern part of Far East Asia can go there, maybe the Southern most part of South Asia, Equatorial Africa and Central America. All of them seem to be placing themselves in zone11. Gives a false image.
Regards,
Arif.

I use 13a from the Puerto Rico map but in tropical areas this type of zone rating isn't very helpful. It is based on the minimum temp and that is not really the defining thing in what you can grow and what you need to protect. Here we need to protect some plants from heat and the maximum temp would be more helpful. Also, some of the tropics have distinct wet and dry seasons (I do) and growing plants under those conditions is much different than a year long rain forest type climate. I guess it helps in locating those of us in the tropics but it doesn't tell us much about whether certain plants will thrive or will need additional water or sun protection.

ps. a max of 32°C is not that common in the tropics except at higher elevations. We have several weeks when it is common for the temps to get to 40°C and sometimes higher. 32°C is more common as a high in the winter, our lows in the winter can occasionally get to 16°C but are generally from 18° to 20°C.

Is anyone aware of a "system" that deals with tropical climates? Perhaps we just need to encourage comments on just this sort of thing. Even though I live in z6a I still find these kinds of comments informative and helpful if I'm trying to overwinter or provide a summer microclimate.

Jonna, agreed but I was basically talking about Equatorial countries and my experience is a bit old. Due to climate change maybe 40 is normal now days but what about balmy countries? Like Singapore, Indonesia, Malaysia, Surinam, South Thailand, Sri Lanka, Cuba, etc. After all every one goes to these countries just due to this reason.
When we in the North freeze and Australia fries plus when the North fries and Australia freezes in both the instances the sun is at the same distance from the Equator, far away. When it is directly over head between winter and summer solstice, the atmosphere on the Equator is thick with a lot of dust, pollution and the heat does not reach down.
Also due to being surrounded by the sea humidity plays a big role which is not reflected in the data base. People living in these countries don't know what a sweater or a jacket is for, other then the educated lot. No pun intended. They live in thatch/reed/bamboo houses and there is no concept of heating, maybe venting. Fans don't run at high speed but at a lazy pace just to dry the sweat. Air-conditioning is used to remove moisture not heat.
Aroids for one grow in these countries and they mark themselves as zone 11. Now people living in actual zone 11 countries think if these plants can grow there why not here and end up in trouble. Just one example. Most people do not globe trot like me and I can understand why they are having trouble. If they had their own zone and all the details were marked down then people can exactly know the climatic conditions.
How it will be solved, I don't know but non of the other sites have taken this aspect into consideration.
Regards,
Arif.

Well, latitude and altitude are the main ways to designate zones although, as you mentioned, proximity to large masses of water change things as well. I'm at a similar latitude to southern Cuba and Río de Janeiro and the types of plants that will grow in both locations are similar but the important difference would be rainfall patterns. We can fairly easily compensate for differences in rainfall in our home gardens so I think that is a less important criteria for home gardeners but more important for farmers.

Most would define equatorial as within around 10° of the equator. Most of those areas are warmer with rainfall more consistent at all times of the year than the areas from 10° to 20° north or south. None of these areas are defined by cold but by rainfall and warmth. Personally, I'd be happy to just know what plants need cold to do well, which need low or high humidity and which need a dry and wet season or all year rainfall.

Jonna, first I was looking at Mexico but now Yucatan which does bring you nearer. Rio, can we go North a bit. If you had said Macio or Fort Aleza but I would rather like Surinam. Any way, you are hitting the nail on the head. "None of these areas are defined by the cold" but neither are they defined by the heat "but by rainfall and warmth", warm and hot there is a difference. Most of these areas have a daily cloudburst of maybe fifteen minutes if not more. Humidity is not low, sometimes a person can feel the density as if in a swimming pool. I am again coming back to Asia. I know most of the people in this area would be interested to know about cold not from the point of view of which plant would do well but which to ignore.
I think we are on the same page but it does seem to be a philosophical discussion unless we set some tangible parameters like what are the maximum and minimum temperatures. "which need low or high humidity", I can understand that from your view point but it is also important from our view point and is not reflected in the database. Singapore, as it is the most developed country in this belt a visit to its met/weather data site should give us a better indication of maximum/minimum mean temperatures and humidity levels over the last two hundred years or so. Sri Lanka/Ceylon, Malaysia their data should also be in black and white over the last two hundred years and quite reliable. Central Africa due to benign condition has never been peaceful but in conflict so data from there is a bit chancy. Brazil, I was there in late 70's early 80's so I am a bit leery about their data. Surinam is lost in a deep hole. Peru, again mountain country. Leaves us only Far East Asia to use as a benchmark.
My mental world map is a bit rusty but isn't Yucatan mountain country? Not fair, just like some one from Kandy setting the parameter. Sri Lanka has one mountain only, famous for Adam's foot print and Kandy is on top of it. I am also in mountain country and thirty miles away the altitude difference is 1500 to 2000 feet, when I post pictures from there people do get confused, how come he is in zone 9 and posting pictures of plants from zone 6 or 7?
" Personally, I'd be happy to just know what plants need cold to do well, which need low or high humidity and which need a dry and wet season or all year rainfall". What about people like Noel? I can understand his climatic conditions and so can you but he is stuck with the database as reference. What about people who try to grow Blue Jade Vine in Texas or Florida after checking the database .
Regards,
Arif.

Jonna, you are at 22N some where in between Karachi and Bombay. What Karachi Bombay area has is one long never ending summer with a weak winter, about 5c and a good spring. You or I are not from Equatorial countries. Karachi is a desert, Euphorbia country.
Regards,
Arif.

Where I am is very flat, a limestone finger sticking out between the Gulf of Mexico and the Caribbean. There are only a very few hills in one part of the peninsula and they are negligible. The rest of the peninsula is between 0 and 40' above sea level. The city I am in, actually my house, is at +20° 57' 49.97", -89° 37' 45.98" so I'm at 20°n. This is the semi arid tropics, we have enormous rainfall but almost all of it is from June to October. It is very dry in the winter and the lows are generally around 20°c and the highs from 30°c to 35° although today it has gotten to 39°c. Because of the dry season, native plants generally are those that need that period of dry in order to bloom. That's a key thing to know about a plant. We are mostly unsuccessful with any plant that needs chilling and many plants that are susceptible to things like powdery mildew and rust will not do well here as they never go dormant and the humidity is high. Roses for instance, it is a pain to grow them and I tend to think of them as annuals.

So, we are not a desert, we have monsoon type rains in the summer. It not as tropical as where Noel is because I don't think they have wet and dry to the same extreme. In the spring, the hottest time of the year here, it can get very very hot and humid with lots of wind. That's when we all start praying for the rains to begin. Once they start, it rains almost every afternoon and that keeps the temperatures lower and things grow as if on steroids.

Fly due East across the Atlantic, you come across the ancient Egyptian kingdom of the Pharaohs (its huge spreading from Atlantic and beyond the Red Sea). When you have said your hellos to the belly dancers, take off again and fly due East and you come across the ancient Persian kingdom of Darius/Cyrus(its huge from Arabia to mid South Asia). Appreciate the beauties and good food. When finished take off again and fly due East and you come across the ancient kingdom of the Laos/Cambodia(its huge spreading from mid South Asia to Pacific). I don't know whose beauties are better but appreciate them. In the morning take off again and fly due East, you reach home.
What have they all got in common? Not the beauties but the SUN and the Pyramids. They all worshiped the sun god Raa. Why? The sun passes overhead. I have spent twenty years of my life in this sun belt and should exactly know about its aridity and heat. You are correct in writing the zone invented by you, there is no zone talking about this extra special belt either.
Conclusion. This Zone scheme does not cater to all conditions but the incorrigible amongst us wont give up trying to grow plants from this area. I also love to dabble for the challenge in these Equatorial area plants. Jonna, cannot blame people who have not appreciated prickly heat one inch in diameter, now can we?
Regards,
Arif.

Yes, we have pyramids here and both a sun and a rain god. Right now we are at the center of the hysteria about the supposed 'end of the world' when the Maya long count turns over on Dec 21. There is a saying in spanish, Si se acaba el mundo. yo me voy para Yucatán. It means 'if the world ends, I'm going to Yucatan' and has been a common phrase for many years. In the past it referred to the lack of natural disasters here, no earthquakes, tornados, volcanos, tidal waves, rarely hurricanes, etc. It has a whole new meaning now but... it's good for tourism

I am looking carefully at ATP corners. In profiles things go up to zone 13b but no maximum/minimum criteria has been set. How ever in the database in the minimum cold hardiness section there is a criteria profile of lowest temperature but things terminate at zone 11? Now lets see what the maximum recommended zone is up to, well it does go up till zone 11 but there is no criteria set as to what is the maximum temperature? It all depends upon individual creativity and how he considers things should be.
After zone 11 it seems Jonna's zone starts and he has taken 13a, so far so good. After Jonna's zone the tropical and the equatorial zones start and it can be given 13b. Now what/where is zone 12? If Jonna's zone is 13a and he lies between Karachi and Bombay, then the minimum temperature at sea level should not go below 18c UNLESS there is a cold wave from some snow covered mountain but the maximum temperature can easily hit 50c with 100% humidity in the rainy season. If there is a sea nearby then the year long average humidity should lie some where near 50%.
If we give 13b to the Equator then maximum temperature will be 32c and minimum at 26c with 100% humidity most of the time. How to explain the discrepancy between 13a and 13b? The intelligent will understand but there should be some criteria for normal every day people, dunces like me.
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Then along comes Melissa to throw out the baby with the bath water, zone 16?? I spent a lot of time trying to sort it out but now I am totally disoriented Oh well, win some lose some, back to the drawing board. Are you some where near the International Date Line, this side or that side? Your luck runs out according to which side you are on but the problem is did the Mayans agree with what we call the Date Line . Jonna, any knowledge or stories about it?
Regards,
Arif.

If Jonna's zone is 13a and he lies between Karachi and Bombay, then the minimum temperature at sea level should not go below 18c UNLESS there is a cold wave from some snow covered mountain but the maximum temperature can easily hit 50c with 100% humidity in the rainy season. If there is a sea nearby then the year long average humidity should lie some where near 50%.

That's a pretty accurate view of my zone with the exception that it very rarely gets near 50°c and then only out in the country farther away from the Gulf. I think it is the tempering effect of the Gulf and the daily afternoon sea breeze that keeps the temps lower here. We do get to 40°+ a few degrees on occasion, mostly in the late spring right before the rains start. Humidity hovers around 50% in the dry season and around 100% in the wet season.

I don't understand your reasoning that the max temp should be 32°c on the equator though. I've been about 10°n in Panama and the temps were higher than that along the coast, in fact it seemed to be hotter than it is here. I was in Singapore once, plus I have some friends who live there, and it is hotter there than here as well. Without altitude my guess is that the avg temps would be higher closer to the equator. Day length would have something to do with it, particularly in the winter. Here we have about an hour difference in sunlight from winter to summer, an even day/night length keeps it from getting hotter in the summer but keeps it warmer in the winter.

Bottom line, the zones we are using here are designed for the USA. Melissa is extrapolating from them and creating a zone 16. I used Puerto Rico which is pretty close. I did a search in spanish for a world planting zone but didn't find one, I didn't try all combinations and may give it another go. I was thinking that there is probably a similar zone set up for Latin America but I'm not at all sure what it would be called. The Argentines have a lot of gardening information, they seem to be a nation of gardeners too. I'd be surprised if they didn't have some type of zoning since their country covers as many diverse areas as it does. Mexico really should have one too and perhaps it does and I'm not finding it. I do belong to a succulent club here at the agricultural university, I will ask about this at the next meeting.

From what I know, the ancient Maya were unaware or uninterested in any areas other than this hemisphere. They did trade up and down the coast perhaps as far as the US in the north and the South American coast to the south - mostly north/south so no date lines needed. They were incredible mathematicians and their calendar is actually more accurate than the current one, there is no need for any 'make up' days or leap years. They are enjoying the world's interest but are not concerned about the end of this Baktun or cycle. All the hotels are full though and the archeological ruins are overflowing with visitors so it's all good. The 'end of the world' special package rate hotel plus party deals are all sold out. Bars and restaurants are all having special events as well. I'm a bit underwhelmed by it all but I'm glad the current Maya are getting some recognition and some income from it.

1) Atmospheric envelope must be twice the thickness of what it is at the poles.
2) Atmospheric density must be more then twice what it is at the poles.
3) If the sun is on top of the sun belt in summer, it subtends at an angle to the Equator (not directly overhead at Equator) so the sun rays are traveling more then twice the distance compared to your area.The colour spectrum changes.
4) Island nations mostly but even for South America's top the moisture laden breeze meets a mountain range which acts as a seal. The sea breeze keeps the temperatures also down.
Singapore.http://app2.nea.gov.sg/index.a...
It is minimum 24c and maximum 31c these days, "Partly cloudy. Thundery showers mainly over southern , eastern and western Singapore in the afternoon".
Malaysia.
The northwest coastal areas of Sabah experiences a rainfall regime of which two maxima and two minima can be distinctly identified. The primary maximum occurs in October and the secondary one in June. The primary minimum occurs in February and the secondary one in August. While the difference in the rainfall amounts received during the two months corresponding to the two maxima is small, the amount received during the month of the primary minimum is substantially less than that received during the month of the secondary minimum. In some areas, the difference is as much as four times.
Here you go. http://www.met.gov.my/index.ph...
Sri Lanka.http://www.meteo.gov.lk/http://www.meteo.gov.lk/index....
Here you have Mount Kandy so some spots lower temperatures but noting below 14c.
Surinam.
German? http://www.meteosur.sr/weather...http://www.meteosur.sr/
Colombia. Jonna you will have to read. Don't worry I can pick up what I need.http://institucional.ideam.gov...
Du Congo go.http://www.meteo-congo-brazza....
Kenya.http://www.meteo.go.ke/pws/wx/...

Jonna, you may have to shift to 12b and leave 13a for the tropical ones.
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So the Mayan Date Line goes North and South from the top of some pyramid?
If a civilization has to be destroyed, what and where does the current civilization originate? Not my poor country, so I won't be worrying much
Regards,
Arif.

Sorry about my tossing in a monkey wrench! Even here on my tiny island there seem to be different zones. 28 miles long, seven at the widest, dry and cactus on the windward east end, wet and jungly on the west..

I lived in an apartment way high, altitude about 900 feet above sea level, high for here anyway, and it was much much cooler than another place I lived that was inland and low. At the same lattitude, Puerto Rico has mountains taller than 3,000 feet that can get much cooler than here.

Another consideration for zones is day/night length. (O NO!! another monkey wrench!!) The days/nights are about 13/11 hours in the summer, and opposite that in the winter.

Tomatoes simply will not pollinate here in the summer. The days are 85-95, and nights are 80-82, and it's just too hot. Tomatoes are a winter crop, just beginning to appear now in December. Spinach sprouts and keels over in a few days.

I would like southern limits for plants, how far south can this or that peach or apple be grown? How about berries? I heard of a tropical blackberry, but couldn't find one for sale. Cold tolerance isn't an issue, hey?

Yes, the closer to the equator, the more equal the days. And the higher the elevation, the cooler.

It is a matter of comparatives. We get summers of 44 C-47 C and winters of -5 C to 3C. As you are further from the Equator, maybe a half hour longer winter is allowed. Tomatoes. Don't grow American hybrids, grow the local variety. As any thing below 10000 feet are considered hills here so I can't consider your three thousand feet as a mountain but elevation does modify temperatures and climate.
You have perfect incubation/growing temperatures, forget Peaches, Pears, Strawberries and Apples just not possible. Grow tropical fruits Kiwi, Mangoes, Pineapples, Jack-fruit, Guavas, Papayas, Citrus and the list goes on.
Regards,
Arif.

And speaking of hurricanes, these islands are subject to tropical storms and hurricanes, June to November.